The present invention relates to a joining method of works, and relates to a joining method of joining a panel to a vehicle body of a vehicle, for example.
For example, a welding technology, such as spot welding or laser welding, or a joining method using an adhesive agent have been used as joining means for joining metal plate members to make a vehicle body in an automobile manufacturing factory.
Japanese Patent Laid-Open Publication No. 6-55277, for example, discloses a weld-bond method using both the spot welding and the adhesive agent, which may further improve a joining using a single joining means. In this weld-bond method, a temporary joining is applied by the spot welding in a vehicle body assembling step (spot welding step), and then the adhesive agent is cured in a drying step (heating step) where the vehicle body passing through a painting step is dried in a paint-drying device (see a flowchart on the top in FIG. 1).
In the meantime, a quick-curing adhesive agent, such as ultraviolet-curing adhesive agent or an adhesive agent made from cyanoacrylate, is known. Further, an adhesive agent having a chain-reacting curing reaction function is also known recently, which is disclosed in U.S. Pat. No. 6,599,954. In this adhesive agent having the chain-reacting curing reaction function, when this adhesive agent is exposed to energy radiation, a heat energy of curing reaction is positively generated within the adhesive agent, and the curing reaction is further effected, like a chain reaction, by the heat energy of curing reaction to successively generate an additional heat energy of curing reaction, so that the adhesive agent can be cured by means of these reaction heat energies.
Herein, in the above-described weld bond method it may take some time for the adhesive agent to be cured, so some additional assist means for temporally fixing, such as spot welding, or fixing with rivets, would be necessary. However, this would cause further a problem in that such temporally-fixing means may need more time to move and set such apparatuses at their proper positions.
On the other hand, the above-described quick-curing adhesive agent would have a disadvantage in that a tack time until a portion that is not exposed to ultraviolet rays comes to be cured is too short. Meanwhile, the above-described adhesive agent having the chain-reacting curing reaction function may not have this advantage, and it may be important to ensure a stable, successive generation of the curing reaction heat for this kind of adhesive agent. For example, if the reaction heat was let go away to an outside portion with influence of a work clearance, a jig, and the like, there may occur a problem in that the curing-chain reaction of the adhesive agent would stop improperly. This improper stop could cause a lack of joining strength obtained, deformation of work with local curing shrinkages of adhesive agent, an improper opening of joining face, and the like.